Page 499 - Clinical Hematology_ Theory _ Procedures ( PDFDrive )

CHAPTER 24 ■ Myelodysplastic Syndromes and Myelodysplastic/Myeloproliferative Neoplasms 483

Characteristics of Chronic
BOX 24.2 TABLE 24.5
Myelomonocytic Leukemia

Blasts*
Characteristics of Chronic Myelomonocytic

Leukemia CMML-1 Peripheral blood <5%

■ Persistent peripher l bloo onocytosis (gre ter th n Bone marrow <10%

1 × 10 /L) CMML-2 Peripheral blood 5%–19%
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■ Less th n 20% yelobl sts, nonbl sts, n pro ono- Bone marrow 10%–19%

cytes in the bloo n bone rrow or

■ Absence o Phil elphi (Ph) chro oso e or BCR-

ABL1 usion gene Presence of Auer rods irrespective of the

■ No evi ence o PDGFRA or PDGFRB ut tion percentage of promonocytes and blasts

■ Dyspl si in one or ore yeloi cell lines *Including promonocytes.

■ In the bsence o yspl si , i gnosis o CMML is sup-

porte by evi ence o n cquire , clon l cytogenetic

or olecul r genetic bnor lity, or onocytosis or T is is the h ll rk o CMML. Neutrophili is co only

t le st 3 onths n exclusion o ll other c uses o observe , with orphologic l bnor lities being present.

onocytosis. Neutrophil precursors (pro yelocytes n yelocytes) usu-

lly ccount or less th n 10% o the leukocytes.

T e bone rrow is hypercellul r in ore th n 75% o
Chronic Myelomonocytic Leukemia p tients. Gr nulocytic proli er tion c n be striking. An

Chronic myelomonocytic leukemia (CMML) is clon l he to- incre se in erythroi precursors y be seen s well.

logic lign ncy th t is ch r cterize by e tures o both n Genetic ssess ent or 11q23 (MLL) n NPM1 in ll

MPNs n n MDS (Box 24.2). T is or o yelo ono- c ses o CMML-2 is vise . I these rkers re positive, it

cytic leuke i is uch less requent th n the cute v riety. r ises the possibility o evolving cute yelo onocytic leu-

Di gnosis o CMML, ccor ing to the FAB cl ssif c tion ke i . SRSF2 is nother potenti l ut tion.

criteri , istinguishes between two istinct or s, CMML-1 Cytoche ic l (Box 24.3) n i unophenotyping o

n CMML-2. A c tegory o CMML-0 y exist in c ses peripher l bloo n bone rrow spir tes re strongly rec-

with less th n 5% bl sts. One shows only n incre se o o en e . I unophenotyping h s been use ul in etect-

ture onocytes, n it h s no rel tionship to the type th t ing e rly tr ns or tion to cute leuke i . T e peripher l

tr ns or s into AML. It is consi ere re ctive onocy- bloo n bone rrow usu lly express the expecte yelo-

tosis. T e other or , in ition to n incre se o ture onocytic ntigens, or ex ple, CD13 n CD33. An

onocytes, shows n incre se o ew onobl sts n pro- incre se percent ge o CD34+ cells h s been ssoci te

onocytes. T is is consi ere to be true CMML n usu- with tr ns or tion (Fig. 24.4).

lly quickly evelops into the M4 or M5 or s o leuke i CMML evelops t e i n ge o 66 ye rs, n the

(AML). T e clinic l sy pto s closely rese ble those o sub- le- e le r tio is 2.4:1. CMML is prece e by n MDS

cute yelogenous leuke i . o i erent subtype in bout one ourth o p tients n is
tr ns or e into cute leuke i in one ourth.

Pathophysiology

Dyshe topoiesis o ll three cell lines is present. T e per-

cent ge o reticulocytes, the tot l peripher l RBC count, n

the pl telet count re typic lly ecre se , lthough the tot l

peripher l WBC count y be nor l or slightly ecre se .

Laboratory Data

CMML inclu es n incre se nu ber o cells in the periph-

er l bloo th t y be orphologic lly n /or unction-

lly bnor l. T e bl st percent ge in the bone rrow

n bloo is lw ys less th n 20%. L bor tory f n ings v ry

between h ving ch r cteristics o MDS n MPNs. P tients

with the BCR-ABL1 usion gene or re rr nge ents o

PDGFRA shoul not be inclu e in this c tegory, nor shoul FIGURE 24.3 Ane i with excess bl sts (RAEB-1 n RAEB-2).

CMML p tients with PDGFRB re rr nge ents be inclu e . (Reprinte ro An erson SC. Anderson’s Atlas o Hematology,

Peripher l bloo s e rs ( ble 24.5) usu lly e onstr te Phil elphi , PA: Wolters Kluwer He lth/Lippincott Willi s &

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persistent onocyte count gre ter th n 1 × 10 /L (Fig. 24.3). Wilkins, Copyright 2003, with per ission.)